Ten years ago, John Wood was a high-flyer. As director of business development in China for Microsoft, the computer giant, he lived in expat luxury in Beijing with an equally high-flying girlfriend. His rent was paid for him, and he flew everywhere business class. He had two drivers, a full-time housekeeper and an enormous salary.

“It was a very good life,” he says softly. “But it was leaving me empty.”

Highly successful professionals all over the world echo that sentiment: what can we do to make our lives more meaningful? Is there more to life than the pursuit of money and careers?

This weekend Wood’s former boss, Bill Gates, stepped down from the helm at Microsoft to focus on his philanthropic work. Gates has discovered that the most rewarding thing to do with wealth is to give it away. It is nearly a decade since Wood also gave up everything he’d been working for to make his dream a reality.

By his late twenties he was on the fast track at Microsoft, ambitious to succeed and earn lots of cash. For more than a decade his day began with early-morning e-mails and finished 13 hours of high-pressured performance later.

“When you’re part of a growing company you get responsibility thrown at you,” he says. “I had a huge team — I got to the office one morning and introduced myself to a guy I’d never met only for him to tell me that I was his boss. I feel lucky to have had the experience, but there came a point when I wanted a break.”

In April 1998, Wood, then 34, took a three-week walking holiday in Nepal. It was the longest holiday he’d taken in nine years: a reward to himself for his high-stress career.

On his first day of vacation he struck up a conversation with a Nepali man whose job it was to find resources for 17 schools. Wood was astonished when he learnt that Nepal’s illiteracy rate was 70%, among the world’s highest.

Intrigued, and keen to learn about “the real Nepal rather than the trekker’s version”, he visited a rural school. There he found the room marked “library” completely empty. The few books in the school (a Danielle Steel romance, an Umberto Eco novel in Italian, the Lonely Planet guide to Mongolia) were under lock and key, considered so precious that the teachers did not want to risk them being damaged by the children.

When he talked to staff about the lack of resources, the teacher said to him: “Perhaps, sir, you will some day come back with books.”

Over the next few days, trekking through the mountains, Wood thought about his most precious memories as a youngster, when his mother read to him at night. He could not envisage a childhood without books.

From a cybercafe in Kathmandu he sent “the best sales pitch of my life” to the 100 people stored in his online address book, asking them to send books care of his parents’ home in America. They poured in. Then in 1999, with his 73-year-old father, he returned to Nepal on a “once in a lifetime” trip to distribute this treasure.

His welcome exceeded anything he had imagined. As he and his father approached with their book-laden donkey train, Nepali students formed a human corridor. They hung marigold garlands around the visitors’ necks and stared entranced at the brightly coloured children’s books, one girl’s face frozen in fear at her first encounter with the teeth of a great white shark.

A teacher told Wood: “You have given our children so much. We have so little to give in return.” Wood felt he had discovered an activity that gave meaning to his life.

He describes the day he went back down the mountain trail to catch his flight home as the worst of his life. “I could have stayed in those rural schools for weeks and weeks,” he says. “The children were so full of joy, smiling and pointing at the pictures and reading to each other. It was so painful getting on that aeroplane to go home. But it was painful for another reason too: I knew that I was going back to rig my whole life with dynamite, blow it up and start over.”

Within weeks he had quit his job at Microsoft to set up Room to Read, a charity to supply books to children in Third World countries. His decision meant sacrificing more than just his salary. His girlfriend, whom he had once thought he was going to marry, was deeply upset. Her “preference was for the glamour of the expatriate life in a big city”, he says. According to Wood, she threw a painting at him. It showed a bench in the shade of a tree. She had told him it represented the place where they would sit together in old age.

“People get used to a certain level of living,” he says reflectively. “It’s easy to get addicted to that lifestyle. People said, ‘But you have everything. How can everything not be enough?’ I had to explain that I didn’t have everything — that what I had wasn't making me happy.”

With his savings and £1m of Microsoft stock, he thought he had enough to work for his charity for no salary for a while; 3½ years later, with the dotcom bubble bursting and the value of his Microsoft stock halved, he still wasn’t earning a penny. “It was a painful time,” he says. “There were so many moments when I thought I should drop it all and go back to my old lifestyle.” Seed funding from foundations that supported social entrepreneurs bought him crucial time and kept the project afloat.

Room to Read has now built and stocked more than 5,100 libraries in Asia and Africa, putting 4m books in the hands of children who had never had access to them before. The charity has also published more than 200 local-language children’s books, and it funds 4,000 long-term scholarships for girls who would otherwise receive no education at all.

“What struck me on that very first visit was that the kids wanted to learn and read but just didn’t have the means to,” Wood says. “When all a child asks you for is a pencil, that’s when you realise something very basic is missing.”

The gap was all the more apparent to Wood because his father, the first in the family to go to university, had stressed the importance of education.

“We lived in a small town in Pennsylvania where there wasn’t a lot of intellectual ferment,” Wood explains. “But we had two libraries through which I learnt about the world. My parents couldn’t afford all the books I wanted, so being able to borrow any book I liked was wonderful.”

His parents had also taught him other lessons: “They always said that having money doesn’t make you a good person, that it’s what you do with your good fortune that matters,” Wood says. “I stumbled across a better way of using what I’d achieved by chance on that walking holiday, so at 35 I decided that chapter one of my life was over. This is chapter two.”

Room to Read prides itself on a creative approach to fundraising that owes much to his insider knowledge of the corporate world. Wood travels on frequent-flier miles donated by a Goldman Sachs banker; Room to Read’s offices in Hong Kong and London are donated by Credit Suisse; and its investors include Accenture, ING and, of course, Microsoft.

“We’ve out-Starbucked Starbucks,” Wood says with a grin. “In their eighth year of trading they opened 1,000 outlets; in our eighth year we opened 1,600 libraries. I say that if the world needs a latte it definitely needs literacy, so if they’re moving that quickly, so should we.”

It’s a model that seems to be working: 2,000 more libraries will open by the end of this year alone and they are on course to have built 13,000 by 2010. “We’re trying to do everything on a truly massive scale,” says Wood, whose book Leaving Microsoft to Change the World, published in a British edition by Collins this month, describes his transformation. “Ultimately this will be the biggest build out of educational infrastructure in the history of the developing world.”

It might look an impossibly grand ambition in print, but there’s something in the earnestness of Wood’s gaze, as well as in the charity’s track record, that makes it sound as achievable as any bullish business plan. And Wood is as devoted to his cause as ever. Now 44 years old, he earns less than he did in the first year after completing his MBA, but he wouldn’t have it any other way.

“I think I have settled, but I’ve settled into a peripatetic existence,” he says. “In some ways my life is the same as it always was; I still work ridiculous hours seven days a week and spend most of my life on a plane, but I’m happier than I’ve ever been.”

On a recent visit by Wood to a school in Vietnam, a teacher took his hand and wept. “I tried to explain to him they had given me something I’d never had before,” Wood says. “The feeling that maybe my prosperity can be used in a better way.

“We live in the biggest era of wealth-creation in human history, but there are children in the developing world who don’t go to school. I feel lucky to have found this as my passion, because otherwise prosperity can be a very empty thing.”